Techno Tantor: November 2015

Saturday, November 28, 2015

Filtering without Lambda or Java 8

I wanted a way to filter generally without using Lambda or Java 8.

	public class CollectionsUtils {
	public static void remove(List<?> items, Filter<Object> filter) {
	Iterator<?> iterator = items.iterator();
	while (iterator.hasNext()) {
	if (filter.shouldRemove(iterator.next())) {
	iterator.remove();
	}
	}
	}
	}

view raw CollectionUtils.java hosted with ❤ by GitHub

	public interface Filter<T> {
	public boolean shouldRemove(T t);
	}

view raw Filter.java hosted with ❤ by GitHub

	List<Map.Entry<String, Object>> list = new ArrayList<Map.Entry<String, Object>>(entries);
	//remove negative values
	CollectionsUtils.remove(list, new Filter<Object>() {
	public boolean shouldRemove(Object o1) {
	Map.Entry<String, Object> entry = (Map.Entry<String, Object>)o1;
	Double d1 = Double.parseDouble(entry.getValue().toString());
	return d1<0.25;
	}
	});

view raw FilteredMap.java hosted with ❤ by GitHub

Monday, November 16, 2015

File path from Class Relative

determine current filesystem location of executed class from the code of this class, in runtime, given that it's executed using java command?

	final File f = new File(
	MyClass.class
	.getProtectionDomain()
	.getCodeSource()
	.getLocation().getPath());

view raw Filepath.java hosted with ❤ by GitHub

http://stackoverflow.com/questions/11747833/getting-filesystem-path-of-class-being-executed

Sunday, November 15, 2015

Creating CORS Web Service for AngularJS

CORS is the ability to allow cross domains scripting. This can be important if you say want to host your website on S3 and have those pages access web services in EC2. I spent TONS of time trying to find how to configure AngularJS to use CORS and what I generally saw was people saying...

"You need to configure the server side for access control, not the client."

Well that's not entirely true.

The example I am using is based on the Spring, Jersey, run-as-ajar example you can find on GitHub. So lets start with the server side then:

	@GET
	@Path("/dates/{ticker}")
	@Produces("application/json")
	public Response getStatements(@PathParam("ticker") String ticker) {

	try {
	CompanyStatements companyStatements = fundamentalsDao.getStatementsForCompany(ticker);
	GsonBuilder gsonBuilder = new GsonBuilder();
	gsonBuilder.registerTypeAdapter(Date.class, new DronzeDateSerializer());
	Gson gson = gsonBuilder.create();
	String json = gson.toJson(companyStatements);

	return Response.status(Status.OK).entity(json)
	.header("Access-Control-Allow-Origin", "*")
	.header("Access-Control-Allow-Headers", "Content-Type")
	.header("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
	.build();
	} catch (Exception e) {
	logger.error(e.getMessage(),e);
	return Response.status(Status.INTERNAL_SERVER_ERROR)
	.entity(getErrorJson())
	.build();
	}
	}

view raw CorsResource.java hosted with ❤ by GitHub

And here is the client side...

	<!DOCTYPE html>
	<html ng-app="dronzeApp">
	<head>
	<title>Hello World, AngularJS - ViralPatel.net</title>
	<script type="text/javascript"
	src="//ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script>
	<script type="text/javascript">
	var dronzeApp = angular.module('dronzeApp', []);

	dronzeApp.config(function($httpProvider) {
	//Enable cross domain calls
	$httpProvider.defaults.useXDomain = true;

	//Remove the header containing XMLHttpRequest used to identify ajax call
	//that would prevent CORS from working
	delete $httpProvider.defaults.headers.common['X-Requested-With'];
	});

	dronzeApp.controller('CompanyStatements', function ($scope, $http) {
	$http.get('http://ec2-52-24-100-54.us-west-2.compute.amazonaws.com:8080/rest/api/statement/dates/AAN')
	.success(function(data) {
	$scope.statements = data;
	});
	});
	</script>

	</head>
	<body>

	<div ng-controller="CompanyStatements">
	<div>Statement ticker: {{statements.ticker}}</div>
	<ul>
	<li ng-repeat="date in statements.statementDates">
	<span>{{date}}</span>
	</li>
	</ul>
	<p>Total number of statements: {{statements.statementDates.length}}</p>
	</div>

	</body>
	</html>

view raw corsclient.html hosted with ❤ by GitHub

Saturday, November 07, 2015

Jenkins Home

[ec2-user ~]$ sudo su -s /bin/bash jenkins bash-4.2$

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